Subaru has finally launched a really special version of the current sedan based Impreza WRX STI (or just WRX STI these days) – the Subaru WRX STI S206. This as usual Japan only special edition is like the earlier S201, S202, S203, S204 and R205. It also reverts back to the ‘S’ moniker instead of the R205 previously. Maybe this change makes perfect sense in terms of keeping in line with tradition.

Anyway, like previous S versions, the car is the pinnacle of Subaru STI tuned cars. These S series cars are JDM road legal cars that basically have a whole bunch of Subaru’s tuning arm STI parts in them and is usually limited to a few hundred units over in Japan. This latest S206 gets all of the option parts plus an additional surprise this time.

It has approximately 320bhp (some say 316bhp) and over 430Nm of torque. The previous R205 model only made do with the same amount so the same amount of magic has been sprinkled on the 2.0liter Flat-Four Subaru engine compared to the standard 300 or so bhp of the stock versions. But Subaru has also claimed better throttle response as well as a flatter torque curve with improved mid-range torque for better drivability. No actual performance figures are given, but I have to think that it’ll be sweeter than usual – I know from experience that the standard 280-300bhp barely makes the WRX STI, and the driver sweat if he’s used to it.

The chassis gets special Bilstein front absorbers (surprising again since its only the front) and unique to the chassis STI springs. There is also a flexible strut tower bar and flexible under bar which increases high speed stability and mid-corner stability too – much like the Yamaha tuned rear strut bar and front under arm bar of the S204 previously. New BBS alloy wheels in 19inch is wrapped with Michelin Pilot Super Sport tyres instead of the usual Subaru specced Bridgestones.

Much like the previous S202, S203 and S204 variants of the previous GD series of WRX STI, the S206 comes with a GT type rear wing option instead of the usual rally spec goalpost rear wing. You could run it wingless too (as is the trend for sedan Subarus these days). The Subaru WRX STI S206 also gets cut-outs on the front fenders – supposedly to reduce air pressure under the wheel arches at very, very high speed - from experience, this should be above and beyond 200km/h as any post 2001 (or GDB and above) WRX STI feels rock solid below that figure.

On the same note, Subaru is also offering a 300 units of the S206 over in Japan, 100 are NBR Challenge Package editions. This model commemorates Subaru’s class win at the Nürburgring 24 Hours and gets the carbonfibre roof and GT rear spoiler like in the photos. Note that the 100 NBR version is already spoken for over in Japan even before its official unveiling at the upcoming 2011 Tokyo Motor Show.